Grinding method and grinding device

ABSTRACT

To grind a peripheral surface of a rotated work ( 10 ), by a rotary grindstone ( 22 ) rotated by a wheel spindle  21,  a rotary brush ( 40 ) is mounted to one side of the rotary grindstone ( 22 ), so that it is rotated along with the rotary grindstone ( 22 ). Subsequently to the grinding of the work ( 10 ) by the rotary grindstone ( 22 ), the rotary grindstone ( 22 ) and the work ( 10 ) are moved axially relative to each other, and a ground surface of the work ( 10 ) is brushed by the rotary brush ( 40 ), whereby the polishing of the ground surface of the work ( 10 ) is achieved. Thus, the shifting of the work as well as an exclusive deflashing device and an exclusive polishing device are not required, which can contribute to a reduction in machining cost.

FIELD OF THE INVENTION

The present invention relates to an improvement in grinding process andapparatus for grinding an outer peripheral surface of a rotated work bya rotary grindstone rotated by a wheel spindle.

BACKGROUND ART

Such a grinding apparatus is already known, as disclosed, for example,in Patent Document 1.

[Patent Document 1]

Japanese Patent Application Laid-open No. 9-300193

A grinding flash and a grinding trace remain on a work ground by arotary grindstone. Therefore, it is a conventional practice that theground work is subjected to a treatment in an exclusive deflashingdevice and an exclusive polishing device, where the removal of a groundflash and the polishing of a ground surface are carried out. In such amethod, however, a lot of labor is required for shifting the work fromthe grinding apparatus to the deflashing device or the polishing device,and, an equipment cost is high due to the need for the exclusivedeflashing and polishing devices. For this reason, it is difficult toreduce the work-grinding cost.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention has been accomplished in view of theabove circumstances, and it is an object of the present invention toprovide grinding process and apparatus, wherein the removal of a groundflash and the polishing of a ground surface can be conductedsubsequently to the grinding of a work, whereby the shifting of the workand the exclusive deflashing and polishing devices are not required,which can contribute to a reduction in machining cost.

To achieve the above object, according to a first aspect and feature ofthe present invention, there is provided a process for grinding an outerperipheral surface of a rotated work by a rotary grindstone rotated by awheel spindle, characterized in that the process comprises the steps ofmounting a rotary brush to one side of the rotary grindstone so as to berotated along with the rotary grindstone, grinding the work by therotary grindstone and then moving the rotary grindstone and the workaxially relative to each other, and brushing a ground surface of thework by the rotary brush, thereby polishing the ground surface of thework.

With the first feature, when the rotary grindstone and the work aremoved axially relative to each other subsequently to the grinding of thework by the rotary grindstone, and the ground surface of the work isbrushed by the rotary brush, the polishing of the ground surface can beachieved. In this manner, the grinding and the polishing can be carriedout continuously and hence, the detachment of the work is not requiredbetween these treatments. Therefore, it is possible to remarkablyshorten the machining time, as compared with the conventional case wherea polishing step is provided specially. This can contribute to areduction in machining cost in cooperation with that an exclusivepolishing device as used in the prior art is not required either.

According to a second aspect and feature of the present invention, thereis provided a process for grinding an outer peripheral surface of arotated work by a rotary grindstone rotated by a wheel spindle,characterized in that the process comprises the steps of mounting arotary brush to one side of the rotary grindstone so as to be rotatedalong with the rotary grindstone, grinding the work by the rotarygrindstone and then moving the rotary grindstone and the work axiallyrelative to each other, and brushing end edges of a ground surface ofthe work by the rotary brush, thereby removing a ground flash of thework.

With the second feature, when the rotary grindstone and the work aremoved axially relative to each other subsequently to the grinding of thework by the rotary grindstone, and the end edges of the ground surfaceof the work are brushed by the rotary brush, the removal of a groundflash can be achieved. In this manner, the grinding and the polishingcan be carried out continuously and hence, the detachment of the work isnot required between these treatments. Therefore, it is possible toremarkably shorten the machining time, as compared with the conventionalcase where a deflashing step is provided specially. This can contributeto a reduction in machining cost in cooperation with that an exclusivedeflashing device as used in the prior art is not required either.

According to a third aspect and feature of the present invention, thereis provided a process for grinding a peripheral surface of a rotatedwork by a rotary grindstone rotated by a wheel spindle, comprising thesteps of mounting a rotary brush to one side of the rotary grindstone soas to be rotated along with the rotary grindstone, grinding the work bythe rotary grindstone and then moving the rotary grindstone and the workaxially relative to each other, and brushing the entire ground surfaceof the work from end edges of the ground surface by the rotary brush,thereby achieving the removal of a ground flash of the work and thepolishing of the ground surface.

With the third feature, the removal of the ground flash of the work andthe polishing of the ground surface can be achieved by moving the rotarygrindstone and the work axially relative to each other subsequently tothe grinding of the work by the rotary grindstone and brushing theentire ground surface of the work from the end edges of the groundsurface of the work by the rotary brush. In this manner, the grinding,the deflashing and the polishing can be carried out continuously andhence, the detachment of the work is not required between thesetreatments. Therefore, it is possible to remarkably shorten themachining time, as compared with the conventional case where adeflashing step and a polishing step are provided specially. This cancontribute to a reduction in machining cost in cooperation with that anexclusive deflashing device and an exclusive polishing device as used inthe prior art are not required either.

According to a fourth aspect and feature of the present invention, thereis provided a grinding apparatus including a rotary grindstone mountedto a wheel spindle to grind an outer peripheral surface of a work by therotation of the rotary grindstone, characterized in that a rotary brushis mounted adjacent to the rotary grindstone for brushing the workhaving a diameter larger than that of the rotary grindstone and groundby the rotary grindstone.

With the fourth feature, the removal of a ground flash and the polishingof a ground surface of the work can be achieved reliably by the brushingusing the rotary brush by only moving the rotary grindstone and the workaxially relative to each other subsequently to the grinding the outerperipheral surface of the work by the rotary grindstone. The detachmentof the work is not required between these treatments and hence, it ispossible to remarkably shorten the machining time. This can contributeto a reduction in machining cost in cooperation with that an exclusivedeflashing device and an exclusive polishing device are not requiredeither.

According to a fifth aspect and feature of the present invention, inaddition to the fourth feature, the rotary brush is formed into avariable-diameter type, so that when the wheel spindle is rotated at alow speed lower than a grinding rotational speed of the rotarygrindstone, the diameter of the rotary brush is smaller than that of therotary grindstone, but when the wheel spindle is rotated at a speedequal to the grinding rotational speed, the diameter of the rotary brushis larger than that of the rotary grindstone.

With the fifth feature, in the dressing of the rotary grindstone carriedout at the low-speed rotation, the rotary brush is contracted to thediameter smaller than the diameter of the rotary grindstone, whereby theinterference of the rotary brush and a dresser with each other can beavoided. In the grinding of the work, the rotary brush is expanded tothe diameter larger than that of the rotary grindstone, whereby theremoval of the ground flash and the polishing of the ground surface canbe carried out substantially simultaneously with the grinding.

According to a sixth aspect and feature of the present invention, inaddition to the fifth feature, the rotary brush is comprised of a brushbody mounted adjacent to the rotary grindstone, and a brush element wireembedded in an outer periphery of the brush body, the brush element wirehaving contraction and expansion properties provided thereto, so thatwhen the brush element wire is in a free state, the brush element wireis in a contracted state in which the diameter of the rotary brush issmaller than that of the rotary grindstone, and when the wheel spindleis rotated at a predetermined rotational speed or more, the brushelement wire is expanded by a centrifugal force, whereby the diameter ofthe rotary brush is larger than that of the rotary grindstone.

With the sixth feature, the rotary brush can be formed into thevariable-diameter type by an extremely simple measure that thecontraction and expansion properties are provided to the brush elementwire.

According to a seventh aspect and feature of the present invention, inaddition to the sixth feature, a single or a plurality of resilient bentportions are formed on the brush element wire to provide the contractionand expansion properties to the brush element wire.

With the seventh feature, the contraction and expansion properties canbe provided to the brush element wire by an extremely simple measurethat the resilient bent portion is formed on the brush element wire andthus, it is possible to provide the rotary brush of thediameter-variable type at a low cost.

According to an eighth aspect and feature of the present invention, inaddition to the fifth feature, the rotary brush is comprised of a brushbody mounted adjacent to the rotary grindstone, and a brush element wireembedded in an outer periphery of the brush body, the brush element wirebeing disposed so that when the brush element wire is in a free state,the brush element is inclined with respect to a radius line of the brushbody, so that the diameter of the rotary brush is smaller than that ofthe rotary grindstone, but when the wheel spindle is rotated at apredetermined rotational speed or more, the brush element wire isallowed to rise toward the radius line by a centrifugal force, so thatthe diameter of the rotary brush is larger than that of the rotarygrindstone.

With the eighth feature, the rotary brush can be formed into adiameter-variable type with an extremely simple structure in which thebrush element wire is disposed in an inclined state and thus, the rotarybrush can be provided at a low cost.

The above and other objects, features and advantages of the inventionwill become apparent from the following description of the preferredembodiments taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a camshaft-grinding apparatus according to afirst embodiment of the present invention;

FIG. 2 is an enlarged sectional view taken along a line 2-2 in FIG. 1;

FIG. 3 is a sectional view taken along a line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along a line 4-4 in FIG. 3 (showing acam whose standard phase is being detected);

FIG. 5 is an enlarged view of a portion indicated by an arrow 5 in FIG.1 (showing a rotary grindstone which is being dressed);

FIG. 6 is a view similar to FIG. 3, but showing a work which is beingground;

FIG. 7 is a sectional view taken along a line 7-7 in FIG. 6; and

FIG. 8 is a view similar to FIG. 7, but showing the work which is beingbrushed;

FIG. 9 is a view similar to FIG. 4, but showing a second embodiment ofthe present invention;

FIG. 10 is a view similar to FIG. 5, but showing a third embodiment ofthe present invention (showing a rotary grindstone which is beingdressed);

FIG. 11 is a view taken in the direction of an arrow 11 in FIG. 10; and

FIG. 12 is a view similar to FIG. 11, but showing a work which is beingground.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described by way of preferredembodiments with reference to the accompanying drawings.

A first embodiment of the present invention will first be described.Referring to FIGS. 1 and 2, an X-direction rail 3 is formed on a table 2on a machine base 1 placed on a floor G to extend in an X-direction, anda Y-direction rail 4 is formed on an upper surface of the machine base 1to extend in a Y-direction perpendicular to the X-direction. A headstock 5 and a tail stock 6 are mounted on the X-direction rail 3, sothat they can be moved toward and away from each other. A main spindle 7is carried in the head stock 5, and a first electric motor 8 forrotating the main spindle 7 is mounted to the head stock 5 and connectedto an outer end of the main spindle 7. A chuck 9 is mounted to an innerend of the main spindle 7.

The table 2 is provided with a tail stock 19 for supporting a work 10for a non-circular rotor by cooperation with the chuck 9 of the headstock 5. The work 10 for the non-circular rotor is a valve-operatingcamshaft in a multi-cylinder engine, in the case of the illustratedexample, and includes a plurality of cams 10 a, 10 b - - - 10 n whichare arranged at predetermined distances in an axial direction, and eachof which comprises a base circle portion 50 having a constant curvatureradius, and a cam lobe 51 leading to circumferentially opposite ends ofthe base circle portion 50 (see FIG. 4). The cams 10 a, 10 b - - - 10 nare different in phases from one another. The camshaft 10is formed by aprecision casting, and outer peripheral surfaces of the plurality ofcams 10 a, 10 b - - - 10 n are to be ground.

A movable table 11 is slidably mounted on the Y-direction rail 4, and amovable table-driving means 12 capable of reciprocally move the movabletable 11 along the Y-direction rail 4 is mounted between the table 2 andthe movable table 11. The movable table-driving means 12 is comprised ofa screw shaft 13 disposed in the Y-direction and threadedly engaged withthe movable table 11, and a second electric motor 14 mounted to thetable 2 and capable of rotating the screw shaft 13 in oppositedirections.

An upper surface rail 15 and a side rail 16 are formed on an uppersurface and a side of the movable table 11 to extend in the X-direction,and a third electric motor 18 is mounted with its output shaft 18 aturned in the X-direction on a motor base 17 which is slidably mountedon the upper surface rail 15. A wheel spindle 21 is carried with itsaxis turned in the X-direction on a wheel spindle stock 20 which isslidably mounted on the side rail 16, and a rotary grindstone 22 forgrinding the outer peripheral surfaces of the cams 10 a, 10 b - - - 10 nof the camshaft 10 sequentially is detachably secured to the wheelspindle 21 by a plurality of bolts 23, 23 (see FIG. 3).

The output shaft 18 a of the third electric motor 18 and the wheelspindle 21 are connected to each other by a driving pulley 24 and adriven pulley 25 fixedly mounted on the output shaft 18 a and the wheelspindle 21 respectively and by a belt 26 wound around the pulleys 24 and25, so that the third electric motor 18 drives the wheel spindle 21 inrotation by its output.

The motor base 17 and the wheel spindle stock 20 are integrallyconnected to each other by a connecting block 28, so that they can beslid simultaneously on the upper surface rail 15 and the side rail 16. Aconnecting block-driving means 29 capable of reciprocally moving theconnecting block 28 along the upper surface rail 15 and the side rail 16is mounted between the connecting block 28 and the movable table 11. Theconnecting block-driving means 29 is comprised of a screw shaft 30disposed in the X-direction and threadedly engaged with the connectingblock 28, and a fourth electric motor 31 mounted to the movable table 11and capable of rotating the screw shaft 30 in opposite directions.

An NC control unit 33 is mounted on the machine base 1. Inputted to theNC control unit 33 are a detection signal from a camshaftrotated-position sensor 34 mounted on the first electric motor 8 forindexing the rotated position of the camshaft 10 from the rotatedposition of the main spindle 7, and a detection signal from a standardphase sensor 35 for indexing the standard phase of the cam 10 a in apredetermined position (the outermost cam 10 a closest to the head stock5 in the illustrated example), in addition to profile data P of the cams10 a, 10 b - - - 10 n on the camshaft 10, data E of phase differencebetween the cams 10 a, 10 b - - - 10 n as well as data S of axialdistances between the cams 10 a, 10 b - - - 10 n. The NC control unitcontrols the operations of the first to fourth electric motors 8, 14, 18and 31 based on these signal and data.

The standard phase sensor 35 is mounted at a tip end of asensor-supporting arm 37 pivotally supported on the wheel spindle stock20. The sensor-supporting arm 37 is capable of being swung between adetecting position A in which the standard phase sensor 35 is opposed tothe outer peripheral surface of the outermost cam 10 a closest to thehead stock 5 and a resting position B in which the sensor 35 is spacedapart from the camshaft 10. An electromagnetic or electric actuator 38is connected to the sensor-supporting arm 37 for swinging thesensor-supporting arm 37 between the two positions A and B.

When the cam 10 a has been rotated from the base circle portion 50toward the cam lobe 51 relative to the standard phase sensor 35, thestandard phase sensor 35 detects a predetermined lift amount of the cam10 a between the base circle portion 50 and the cam lobe 51, and thedetection signal of the standard phase sensor 35 is input as a signalindicative of the standard phase of the cam 10 a to the NC control unit33. The type of standard phase sensor 35, which can be used, may be anyof a non-contact type and a contact type.

As shown in FIGS. 3 and 4, a rotary brush 40 is mounted to the wheelspindle 21 adjacent the rotary grindstone 22. The rotary brush 40 iscomprised of an annular brush body 41, a large number of metal wires 42,42 as brush element wires embedded in the brush body 41, and a pair ofwire-protecting plates 43, 43 opposed to opposite sides of the wires 42,42, while clamping the brush body 41 therebetween. The brush body 41 andthe wire-protecting plates 43, 43 are secured to the wheel spindle 21along with the rotary grindstone 22 by the bolts 23, 23.

To embed the wires 42, 42, a large number of through-bores 44, 44 aremade axially in a plurality of rows in the brush body 41 and arrangedcircumferentially of the brush body 41, and two tip ends of the wires42, 42 each folded into two at the central portion are inserted throughthe every two circumferentially or axially adjacent through-bores 44, 44from the side of the inner periphery of the brush body 41, and each ofthe wires 42 is adhesively bonded or brazed in each of the through-bores44. Each of the wires 42 extends radially outwards from the brush body41 and has a A-shape resilient bent portion 42 a. When the wheel spindle21 is in a stopped state or in a low-speed rotational state in which itis being rotated at a low speed lower than a usual grinding rotationalspeed, the tip end of each wire 42 is positioned at a location radiallyinside the outer peripheral surface of the rotary grindstone 22, butwhen the rotational speed of the wheel spindle 21 is increased to nearthe usual grinding rotational speed, the resilient bent portion 42 a isstretched by a centrifugal force, so that the tip end of the wire isallowed to protrude radially outwards from the outer peripheral surfaceof the rotary grindstone 22 (see FIGS. 6 and 7). In this way, the rotarybrush 40 is formed into a variable-diameter type in which its diameter,i.e., the diameter of the group of the wires 42, 42 can be decreased tosmaller, or increased to larger than the outside diameter of the rotarygrindstone 22.

As shown in FIGS. 1 to 5, a dressing motor 45 is mounted to a side ofthe head stock 5 closer to the movable table 11 with its output shaft 45a parallel to the main spindle 7, and a diamond dresser 46 capable ofdressing the rotary grindstone 22 is mounted to the output shaft 45 a.

The operation of the first embodiment will be described below.

First, to carry out the dressing of the rotary grindstone 22, the outerperipheral surface of the rotary grindstone 22 rotated along with thewheel spindle 21 is brought into contact with the diamond dresser 46 andfed axially, while rotating the wheel spindle 21 at a low speed by theoperation of the third electric motor 18 in a state in which the diamonddresser 46 is being rotated at a high speed by the operation of thedressing motor 45, as shown in FIG. 5.

During such dressing of the rotary grindstone 22, the rotational speedof the wheel spindle 21 is relatively low and hence, each of the wires42 of the rotary brush 40 is in contracted state and thus, the diameterof the rotary brush 40 is smaller than that of the rotary grindstone 22.Therefore, it is possible to avoid the interference of the rotary brush40 with the diamond dresser 46.

Now, to grind the outer peripheral surfaces of the plurality of cams 10a, 10 b - - - 10 n of the camshaft 10 formed by the precision casting,first of all, the opposite ends of the camshaft 10 are supported by thechuck 9 of the head stock 5 and the tail stock 19. Then, thesensor-supporting arm 37 is retained in the detecting position A, andthe standard phase sensor 35 is opposed to the outer peripheral surfaceof the outermost cam 10 a closest to the head stock 5 (see FIG. 4). Thecamshaft 10 is rotated at a very low speed through the chuck 9 by thefirst electric motor 8 on the head stock 5. When the base circle portion50 and the cam lobe 51 of the cam 10 a are moved past before a detectingportion of the standard phase sensor 35 in response to the rotation ofthe camshaft 10, the standard phase sensor 35 detects the predeterminedlift amount of the cam 10 a, and the detection signal is input as thestandard phase signal to the NC control unit 33. Thereafter, thesensor-supporting arm 37 is turned immediately to the resting position Bby the actuator 38 to move the standard phase sensor 35 away from thecam 10 a. Thus, it is possible to avoid that the standard phase sensor35 is exposed to a scattered grinding liquid.

When the standard phase signal is input to the NC control unit 33 fromthe standard phase sensor 35, the NC control unit 33 controls theoperations of the first to fourth electric motors 8, 14, 18 and 31 basedon the signal input from the camshaft rotated position sensor 34 and thedata P, E and S previously input thereto to reciprocally move themovable table 11 in the Y-direction and feed it at the very low speed inthe X-direction while rotating the rotary grindstone 22 at apredetermined grinding rotational speed, whereby the outer peripheralsurface of the cam 10 a is ground from one end to the other end by therotary grindstone 22.

During such grinding, the rotary brush 40 rotated at the relatively highspeed along with the rotary grindstone 22 has a diameter increased tolarger than that of the rotary grindstone 22 by stretching of theresilient bent portion 42 a of each of the wires 42 due to a centrifugalforce, as shown in FIGS. 6 and 7. Therefore, if the rotary grindstone 22is fed in the X-direction subsequently to the grinding, the rotary brush40 having the diameter larger than that of the rotary grindstone 22 canbrush the ground surface of the cam 10 a from one of its end edgestoward other end edge, as shown in FIG. 8.

If the opposite end edges and the ground surface of the cam 10 a arebrushed carefully in the above-described manner, the removal of theground flashes and the polishing of the ground surface can be achievedreliably subsequently to the grinding of the cam 10 a. If the oppositeend edges of the cam 10 a are brushed concentratedly, the removal of theground flashes can be achieved subsequently to the grinding of the cam10 a. If the ground surface of the cam 10 a is brushed concentratedly,the polishing of the ground surface can be achieved subsequently to thegrinding of the cam 10 a.

If the grinding of the one cam 10 a and the deflashing and/or thepolishing are finished in the above-described manner, the NC controlunit 33 actuates the fourth electric motor 31 to shift the connectingblock 28 over only the distance between the adjacent cams 10 a, 10b - - - 10 n in the X-direction, whereby the next cams 10 b - - - 10 nare ground and deflashed and/or polished sequentially and simultaneouslyin a similar manner by the rotary grindstone 22 and the rotary brush 40.

Since the predetermined lift amount between the base circle portion 50and the cam lobe 51 of the cam 10 a is detected by the standard phasesensor 35, whereby the standard phase of the cam 10 a is indexed, asdescribed above, the indexing of the standard phase of the cam 10 a canbe performed properly even if a special recess is not formed around theouter periphery of the camshaft 10, thereby providing a decrease ingrinding margin of the cam 10 a, 10 b - - - 10 n, thus, a shortening ofgrinding time.

By continuously conducting the grinding, deflashing and/or polishing ofthe cam 10 a - - - 10 n, as described above, the detachment of the work,i.e., of the camshaft 10 is not required between these treatments. Thus,it is possible to remarkably shorten the machining time, as comparedwith the prior art in which a deflashing step and a polishing step arespecially provided, thereby contributing to a reduction in machiningcost, in cooperation with that exclusive deflashing and polishingdevices as used in the prior art are not required either.

The rotary brush 40 is formed into a variable-diameter type by formingthe resilient bent portion 42 a on each of the wires 42 and hence, canbe provided with a simple structure and at a low cost.

A second embodiment of the present invention shown in FIG. 9 will now bedescribed.

The second embodiment is different from the previous embodiment inrespect of the arrangement of a rotary brush 40. More specifically,through-bores 44, 44 are made in a brush body 41 and arrangedcircumferentially in a large number of sets with the adjacent twothereof disposed in a V-shape on opposite sides of a radius line R toform a pair. Two tip ends of a wire 42 bent into a V-shape at itscentral portion are inserted through each of the pairs of thethrough-bores 44, 44 from the side of an inner periphery of the brushbody 41, and the wire 42 is brazed in each of the through-bores 44. Thewire 42 bent into the V-shape is inclined with respect to the radiusline R of the brush body 41 in its free state, so that its tip end islocated radially inside the outer peripheral surface of the rotarygrindstone 22, as shown by a solid line in FIG. 9, whereby the diameterof the rotary brush 40 is smaller than that of the rotary grindstone 22.However, when the wheel spindle 21 is brought into a predeterminedhigh-speed rotational state, the wire 42 is allowed to rise toward theradius line R by a centrifugal force, as shown by a dashed line in FIG.9, so that its tip end protrudes radially outwards from the outerperipheral surface of the rotary grindstone 22, whereby the diameter ofthe rotary brush 40 is larger than that of the rotary grindstone 22.

Therefore, as in the previous embodiment, in the low-speed rotationalstate of the wheel spindle 21, the dressing of the rotary grindstone 22is possible without being obstructed by the rotary brush 40. In thehigh-speed rotational state of the wheel spindle 21, the grinding andthe deflashing and/or polishing of each of the cams 10 a, 10 b - - - 10n of the camshaft 10 can be carried out by the rotary grindstone 22 andthe rotary brush 40.

In addition, the rotary brush 40 formed with the large number of wires42, 42 each bent into the V-shape on the opposite sides of the radiusline R of the brush body 41 is also of a simple structure and hence, canbe provided at a low cost.

The arrangement of the other components is similar to that in theprevious embodiment and hence, portions or components corresponding tothose in the previous embodiment are designated by the same numerals andsymbols in FIG. 9 and the description of them is omitted.

Finally, a third embodiment of the present invention shown in FIGS. 10to 12 will be described.

In the third embodiment, a pair of rotary brushes 40, 40 are disposedadjacent on opposite sides of the rotary grindstone 22 and secured tothe wheel spindle 21 along with the rotary grindstone 22 by a pluralityof bolts 23, 23.

A large number of guide bores 52, 52 are made in a brush body 41 of eachof the rotary brushes 40 to extend radially with its radially outer endopening into an outer peripheral surface of the brush body 41, and anannular groove 53 is formed on one side of the brush body 41 to permitradially inner ends of the guide bores 52, 52 to communicate alltogether. An annular retaining ring 54 is disposed within the annulargroove 53, and a large number of bundles of wires 42 wound around theretaining ring 54 are disposed in the large number of guide bores 52,52, so that their tip ends protrude to the outside of the guide bores52, 52. An adhesive 55 is filled in the annular groove 53, wherebycoupled portions of the retaining ring 54 and the wires 42 are fixed tothe brush body 41. Each of the wires 42 is formed into a zigzag shapewith a large number of resilient bent portions 42 a, 42 a arranged in aline so as to be capable of expanding and contracting, and when eachwire 42 is in a free state, it has been contracted, whereby the diameterof the rotary brush 40 is smaller than that of the rotary grindstone 22,as shown in FIGS. 10 and 11. However, when the wheel spindle 21 isbrought into a predetermined high-speed rotational state, each of thewires 42 is stretched by a centrifugal force, whereby the diameter ofthe rotary brush 40 is larger than that of the rotary grindstone 22, asshown in FIG. 12.

Therefore, in the low-speed rotational state of the wheel spindle 21,the dressing of the rotary grindstone 22 is possible without beingobstructed by the rotary brush 40 as in the first embodiment. In thehigh-speed rotational state of the wheel spindle 21, the grinding andthe deflashing and/or polishing of each of the cams 10 a, 10 b - - - 10n of the camshaft 10 can be conducted by the rotary grindstone 22 andthe rotary brush 40.

In addition, the rotary brush 40 formed of the large number of wires 42,42 disposed radially and each bent into the zigzag shape is also of asimple structure and hence, can be provided at a low cost.

Since the pair of rotary brushes 40, 40 are disposed adjacent on theopposite sides of the rotary grindstone 22, even when the camshaft 10 isground from any of left and right directions, the removal of groundflashes and/or the polishing is possible, which is advantageous.

The arrangement of the other components is similar to those in theprevious embodiments and hence, portions or components corresponding tothose in the previous embodiments are designated by the same numeralsand symbols in FIGS. 10 to 12 and the description of them is omitted.

Although the preferred embodiments of the present invention have beendescribed in detail, it will be understood that various modifications indesign may be made without departing from the scope of the inventiondefined in claims. For example, in the rotary brush 40 in the firstembodiment, the wire-protecting plate 43 closer to the rotary grindstone22 can be disused, and the rotary grindstone 22 can serve as awire-protecting member. A brush element wire made of a synthetic resincan be used for the rotary brush 40 in place of each of the wires 42, 42made of the metal. The standard phase sensor 35 may be mounted at aplace other than the grindstone 20 such as the table 2. To conduct thegrinding, the deflashing and/or polishing of the work 10 in theabove-described embodiment, the rotary brush 40 is moved axiallyrelative to the work 10, but the work 10 may be moved axially.

1. A process for grinding an outer peripheral surface of a rotated work(10) by a rotary grindstone (22) rotated by a wheel spindle (21),characterized in that said process comprises the steps of mounting arotary brush (40) to one side of said rotary grindstone (22) so as to berotated along with said rotary grindstone (22), grinding said work (10)by said rotary grindstone (22) and then moving said rotary grindstone(22) and said work (10) axially relative to each other, and brushing aground surface of said work (10) by said rotary brush (40), therebypolishing the ground surface of said work (10).
 2. A process forgrinding an outer peripheral surface of a rotated work (10) by a rotarygrindstone (22) rotated by a wheel spindle (21), characterized in thatsaid process comprises the steps of mounting a rotary brush (40) to oneside of said rotary grindstone (22) so as to be rotated along with saidrotary grindstone (22), grinding said work (10) by said rotarygrindstone (22) and then moving said rotary grindstone (22) and saidwork (10) axially relative to each other, and brushing end edges of aground surface of said work (10) by said rotary brush (40), therebyremoving a ground flash of said work (10).
 3. A process for grinding anouter peripheral surface of a rotated work (10) by a rotary grindstone(22) rotated by a wheel spindle (21), characterized in that said processcomprises the steps of mounting a rotary brush (40) to one side of saidrotary grindstone (22) so as to be rotated along with said rotarygrindstone (22), grinding said work (10) by said rotary grindstone (22)and then moving said rotary grindstone (22) and said work (10) axiallyrelative to each other, and brushing the entire ground surface of saidwork (10) from end edges of the ground surface by said rotary brush(40), thereby achieving the removal of a ground flash of said work (10)and the polishing of the ground surface.
 4. A grinding apparatusincluding a rotary grindstone (22) mounted to a wheel spindle (21) togrind an outer peripheral surface of a work (10) by the rotation of therotary grindstone (22), characterized in that a rotary brush (40) ismounted adjacent to said rotary grindstone (22) for brushing the work(10) having a diameter larger than that of said rotary grindstone (22)and ground by said rotary grindstone (22).
 5. A grinding apparatusaccording to claim 4, wherein said rotary brush (40) is formed into avariable-diameter type, so that when said wheel spindle (21) is rotatedat a low speed lower than a grinding rotational speed of said rotarygrindstone (22), the diameter of said rotary brush (40) is smaller thanthat of said rotary grindstone (22), but when said wheel spindle (21) isrotated at a speed equal to said grinding rotational speed, the diameterof said rotary brush (40) is larger than that of said rotary grindstone(22).
 6. A grinding apparatus according to claim 5, wherein said rotarybrush (40) is comprised of a brush body (41) mounted adjacent to saidrotary grindstone (22), and a brush element wire (42) embedded in anouter periphery of said brush body (41), said brush element wire (42)having contraction and expansion properties provided thereto, so thatwhen said brush element wire (42) is in a free state, said brush elementwire (42) is in a contracted state in which the diameter of said rotarybrush (40) is smaller than that of said rotary grindstone (22), and whensaid wheel spindle (21) is rotated at a predetermined rotational speedor more, said brush element wire (42) is expanded by a centrifugalforce, whereby the diameter of said rotary brush (40) is larger thanthat of said rotary grindstone (22).
 7. A grinding apparatus accordingto claim 6, wherein a single or a plurality of resilient bent portions(42 a) are formed on said brush element wire (42) to provide thecontraction and expansion properties to said brush element wire (42). 8.A grinding apparatus according to claim 5, wherein said rotary brush(40) is comprised of a brush body (41) mounted adjacent to said rotarygrindstone (22), and a brush element wire (42) embedded in an outerperiphery of said brush body (41), said brush element wire (42) beingdisposed so that when said brush element wire (42) is in a free state,said element wire (42) is inclined with respect to a radius line (R) ofsaid brush body (41), so that the diameter of said rotary brush (40) issmaller than that of said rotary grindstone (22), but when said wheelspindle (21) is rotated at a predetermined rotational speed or more,said brush element wire (42) is allowed to rise toward said radius line(R) by a centrifugal force, so that the diameter of said rotary brush(40) is larger than that of said rotary grindstone (22).